Richard kothe



7 UNITED STATES PATENT, OFFICE.

RICHARD KOTH'E, FRIEDRICH REINGRUBER, AND HUGO HASSENOAMP, F ELBERFELD, GERMANY, ASSIGNORS TO THE FARBENFABRIKEN, VORMALS FR. BAYER & 00, OF SAME PLACE.

BLUE COLORING-MATTER.

SPECIFICATION forming part of Letters Patent No. 506,918, dated October 17, 1893.

Application filed May 26, 1898. Serial No. 475,631. (Specimens) Patented in France November 29, 1892,11'0. 225,980; in Italy December 10, 1892, XXVII, 33.120, LXV, 98.

To all whom it may concern..-

Be it known that we, RICHARD KOTHE,

FRIEDRICH REINGRUBER, and HUGO HAssEN- CAMP, chemists and doctors of philosophy, 5 subjects of the Emperor of Germany, residing at Elberfeld, Prussia, Germany, (assignors to the FARRENEABRIKEN, VORMALS FR. BAYER & 00., of Elberfeld,) have invented a new and useful Improvement in the Manufacture of Blue Coloring-Matter, (for which the aforesaid FARBENFABRIKEN, VORMALS FR. BAYER 85 00., of Elberfeld, has already obtained Letters Patent in France, No. 225,980, dated November 29, 1892; in Italy,Vol. XXVII, No. 33,120, Vol. LXV, No. 98, dated December 10, 1892;) and we do hereby declare the following to be a full, clear, and exact description of our invention.

Our invention relates to the manufacture of blue tripheuyl-methane dye-stuffs by condensing equimolecular proportions of tetramethyldiamidobenzhydrol (or tetraethyldiamidobenzhydrol) and alpha naphthylaminmono sulfo acid (NH :SO H:=1:2), subsez 5 quently sulfonating the resulting product and finally oxidizing the thus obtained leuco co mpound.

' In carrying out our invention we can proceed as follows: 2.3 parts, by weight, of alpha 3o naphthylaminmono sulfo acid (NH :SO H= 1:2) are mixed with 2.7 parts, by weight, of tetramethyldiamidobenzhydrol (or the corresponding quantity of tetraethyldiamidobenzhydrol.) About twenty parts, by weight, of 3 5 water acidulated with 2.5- parts, by weight, of sulfuric acid Baum) are added to the above mixture. The resulting mixture is heated for a short time at about from to centigrade, till the tetramethyldiamido- 4o benzhydrol employed isno longer distinguishable. After this time, the mass is poured into about ten parts, by weight, of water, adding a small excess of sodium carbonate. The sodium salt of the thus formed leuco mono sulfo 5 product separates in bright white needles or scales, which dissolve in cold water with difficulty. Then, after filteringoff, pressing and drying ten parts, by weight, of the above sodium salt having the formula:

. slacked lime.

sonve are gradually stirred into forty parts, by weight, of fuming sulfuric acid (containing 6 thirty per cent. of anhydrid). The sulfuric 0 acid liquid is heated for about thirty-six hours at 30 centigrade. When the sulfonation is complete, the reaction mixture is poured on ice, and the sulfuric acid contained therein is neutralized with sodium carbonate, the new leuco disulfo acid, together with a part of the formed sodium sulfate, being separated in form of a cloudy mass. The latter is dissolved in hot water, and this watery solution is then neutralized with calcium carbonate or The solution containing the sodium salt of the leuco disulfo acid is filtered off from the precipitated calcium sulfate The sodium salt of the formed leuco disulfo,

acid has the following composition:

In order to oxidize the above leuco disulfo acid, a quantity of the watery solution of the aforesaid sodium salt which corresponds to ten parts, by weight, of the above leuco mono- 9o sulfo acid, is mixed with such a quantity of water, that the whole quantity of water employed is one hundred parts, by weight, fifty parts, by weight, of a paste of lead dioxid (containing ten percent. of lead dioxid) after 5 well mixing with fifteen parts, by weight, of diluted acetic acid (containing fifty per cent. of pure acetic acid) are introduced on continnous stirring into the above solution of the sodium salt of the leuco disulfoacid. The formation of the dye-stuif is complete within a short time. After adding five parts, by weight, of sodium sulfate, the formed lead sulfate is filtered ofi. The resulting solution of the dye-stud isevaporated to' dryness'andinto blue on the addition of a great aecess of ice-water. With concentrated hydrochloric acid (21 Baum) a yellowish-brown solution is formed. On the addition of very strong soda-lye to its concentrated watery solution a violet precipitate is formed at first, which dissolves with a blue color on adding water, while the resulting liquid becomes almost colorless after standing for some time. v

The dye-stuff produces clear blue shades on wool in an acidulated bath and also is suitable for printing purposes, as it yields clear blue shades fast to the actionof alkalies and acids. The shades produced on wool and cotton do not change theirhues in artificiallight. An analogous result is obtained, if instead of condensing alpha naphthylamin sulfo acid -(NH SO H= 1: 2) with tetramethyl (or ethyl) diamidobenzhydrol, sulphonatingwe claim as new, and desire to secure by Letters Patent, is-

1. The process for the production of new triphenylmethane dye-stuffs by combining equimolecular proportions of tetramethyl (or ethyl) diamidobenzhydrol and alpha naphthylamin sulfo-acid (NH S0 H:l: 2), sulfonating the resulting-lenco compound and oxidizing the thus obtained new leuco sulfo acid (or its salts) in the manner as hereinbefore described.

' 2. As a new article of manufacture the blue coloring-matter having probably the formula:

on-c-o mmm,

(in which formulaR signifiesmethyl or'etliyl), forming adark powder with bronze luster, easily soluble-in water"with bluishviolet color, in alcoholand pure aceticacid witha clear blue color, dissolving'in concentrated sulfuric acid with a reddish-brown color, whichturns into blue on the addition of=a great'excessof ice-water,beingseparated, on adding very strong soda-lye to its concentrated solution inw-aten in reddish-violet flakes, which dissolve again" on adding water to this solution; producing when fixed on woo1,.or printed on cotton, clear blue shades fast against the action of alkalies and acids. In testimony whereof we have signed our names in the presence of two'subscribingwitnesses;

RICHARD KOTHE.- FRIEDRICH REINGRUBER. I HUGO HASSENCAMPQ Witnesses:

WILLIAM EssENWEIN, RUDOLPH FRICKE. 

